intel-iommu: Fix section mismatch dmar_ir_support() uses dmar_tbl.

dmar_tbl is declared as __initdata, but dmar_ir_support() is not declared
as an __init function.  Fix is simple since the only caller of dmar_ir_support
(intr_remapping_supported) is an __init function.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>